Adaptive Light Source Control for Landmark-Based Optical Localization
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Solution Overview
Problem
Existing optical localization systems for indoor navigation face challenges such as unreliable GNSS signals, signal attenuation, and multi-path effects, especially in complex environments with varying lighting conditions and metal obstacles. Additionally, these systems struggle with scaling to larger spaces and accurately tracking objects due to errors in pose estimation and feature recognition.
Innovation Solution
A method for controlling a light source that involves using pose estimates of a camera, a landmark map with 3D location information, an illumination model describing the relationship between emission and reflection illumination powers, and a predefined threshold reflection illumination power. This method determines optimized emission illumination powers and illumination time courses to ensure reliable detection of landmarks, thereby improving pose estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical localization systems use standard image sensors with limited dynamic range, then device complexity is reduced, but measurement precision deteriorates due to inability to capture wide range of lighting conditions
Solution Approach 1:
The patent implements dynamic adjustment of image sensor parameters (exposure time, gain, aperture) based on real-time scene illuminance estimation. The system continuously adapts sensor configuration to match current lighting conditions, enabling accurate feature extraction across varying illuminance levels from full daylight (10,000lux) to full moon (0.1lux) conditions without requiring multiple specialized sensors
Solution Approach 2:
The system changes operational parameters of the image sensor (exposure time, gain settings, aperture) according to the estimated scene illuminance. By dynamically modifying these parameters, the system maintains optimal signal-to-noise ratio and dynamic range utilization across different lighting conditions, resolving the contradiction between measurement precision and device complexity
2Measurement precision
If optical localization systems add illuminance to the scene using torches or strobes, then measurement precision improves, but use of energy increases
Solution Approach 1:
The patent implements periodic or pulsed illumination rather than continuous lighting. The light source (torch/strobe) is activated only during specific intervals when image capture is required, and the duration/intensity is optimized based on current scene illuminance conditions. This periodic activation pattern maintains feature detection reliability while dramatically reducing overall energy consumption compared to continuous illumination
Solution Approach 2:
The system applies illumination only when and where needed - using partial illumination (localized light sources) rather than illuminating the entire scene continuously. The illumination is applied selectively during image capture moments and at intensities sufficient for the specific lighting conditions, avoiding excessive energy consumption while maintaining measurement precision
3Adaptability or versatility
If optical localization systems use inside-out tracking with SLAM, then adaptability improves, but measurement precision deteriorates due to error accumulation in map generation
Solution Approach 1:
The patent incorporates feedback mechanisms where the system continuously monitors feature detection quality and pose estimation accuracy. Based on this feedback, it adjusts sensor parameters, illumination settings, and feature selection strategies to maintain measurement precision. The system uses detected features to refine the map and correct drift, creating a closed-loop control that mitigates error accumulation while preserving adaptability to unknown environments
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enhances the robustness of optical localization systems by optimizing light emission to compensate for varying lighting conditions and improve feature detection, thereby reducing errors in pose estimation and enabling more accurate indoor navigation.
Implementation Method 1
the light source should be operated to emit light which has an emission illumination power and for a time period which is equal to the determined illumination time course
Implementation Method 2
an illumination model describing a relationship between an emission illumination power and reflection illumination power
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling a light source (7), the method using (a) at least one pose estimate (1) of a camera (8) configured to capture one or more images of a scene of interest (13) which comprises at least one landmark (9), as said light source is operated to emit light which illuminates said scene of interest, (b) a landmark map (2) comprising at least 3D location information of a plurality of landmarks comprising the at least one landmark in the scene of interest, (c) an illumination model (3) describing a relationship between an emission illumination power and reflection illumination power, wherein said emission illumination power is the power of light emitted by the light source (7) to illuminate said scene of interest, and said reflection illumination power is the illumination power of light reflected by one or more landmarks in said scene of interest and received by the camera, and (d) a predefined threshold reflection illumination power (4). The method comprises the following steps: (a) determining (5), for at least one of the plurality of landmarks, at least one optimized emission illumination power of light (6) to be emitted by the light source, and an illumination time course (6) during which the light source should be operated to emit light which has an emission illumination power which is equal to the at least one optimized emission illumination power, using (i) the at least one pose estimate (1) of the camera, (ii) the 3D location information of the at least one of the plurality of landmarks, (iii) the illumination model (3), and (iv) the predefined threshold reflection illumination power (4); and (b) operating the light source (7) to emit light which has an emission illumination power which is equal to the at least one optimized emission illumination power (6), for a time period which is equal to the determined illumination time course (6).